1. Field of the Invention
This invention relates to a liquid desiccant regenerating systems for use with dehumidifying apparatus, and is directed more particularly to a system for maintaining the water content of desiccant within a selected range.
2. Description of the Prior Art
The use of liquid desiccants, such as lithium chloride and calcium chloride, for dehumidifying air is well known. In the course of removing water from the air, the desiccant absorbs moisture, becomes diluted, and must be regenerated, that is, must be stripped of its water content to a degree such that the desiccant is relatively concentrated and more readily able to absorb moisture from the air.
Regeneration usually requires heating the desiccant to drive off the excess water. Alternatively, a hot gas may be passed over the desiccant to absorb the excess moisture. Another alternative regeneration method includes heating the desiccant and passing a gas through the desiccant. In one typical application, the desiccant is conveyed to a boiler, where the dilute liquid desiccant is heated and the excess moisture is removed in the form of steam. The resulting concentrated desiccant is then conveyed, though heat exchange means, to a desiccant reservoir, or sump, from which the desiccant is drawn for dehumidifying operations.
In such systems, it is critical that the proper concentration of desiccant be discharged from the sump for use in the dehumidifying system.
In systems in common use, a level sensor and switch monitors the level of desiccant in the sump, but not the concentration, or density, of the desiccant. In the event of a desiccant leak or overcharge, the sensors detect the change in level, which is interpreted to indicate an erroneous desiccant concentration.
It is deemed desirable to have available a system by which the density, and thereby water content, of the desiccant is maintained in a desired range, without regard to the level of the desiccant in the desiccant sump.